ci: Update maxtrix.include from PHP 5.3 to PHP 7.2

Author: DannyvdSluijs

.github/workflows/continuous-integration.yml

@@ -27,10 +27,10 @@ jobs:
         dependencies: [highest]
         experimental: [false]
         include:
-          - php-version: "5.3"
+          - php-version: "7.2"
             dependencies: highest
             experimental: false
-          - php-version: "5.3"
+          - php-version: "7.2"
             dependencies: lowest
             experimental: false
 #          - php-version: "8.0"